4548-45-2Relevant articles and documents
Deaminative chlorination of aminoheterocycles
Cornella, Josep,Faber, Teresa,Gómez-Palomino, Alejandro,Ghiazza, Clément
, (2021/12/23)
Selective modification of heteroatom-containing aromatic structures is in high demand as it permits rapid evaluation of molecular complexity in advanced intermediates. Inspired by the selectivity of deaminases in nature, herein we present a simple methodology that enables the NH2 groups in aminoheterocycles to be conceived as masked modification handles. With the aid of a simple pyrylium reagent and a cheap chloride source, C(sp2)?NH2 can be converted into C(sp2)?Cl bonds. The method is characterized by its wide functional group tolerance and substrate scope, allowing the modification of >20 different classes of heteroaromatic motifs (five- and six-membered heterocycles), bearing numerous sensitive motifs. The facile conversion of NH2 into Cl in a late-stage fashion enables practitioners to apply Sandmeyer- and Vilsmeier-type transforms without the burden of explosive and unsafe diazonium salts, stoichiometric transition metals or highly oxidizing and unselective chlorinating agents. [Figure not available: see fulltext.]
Preparation method of 2-chloro-5-nitropyridine
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Paragraph 0083-0091, (2020/06/17)
The invention provides a preparation method of 2-chloro-5-nitropyridine. The preparation method comprises the following steps: preparing 2-hydroxy-5-nitropyridine by taking 2-nitroacetaldehyde diethylacetal as an initial raw material through two methods; and then carrying out a chlorination reaction on the 2-hydroxy-5-nitropyridine and a chlorination reagent to prepare the 2-chloro-5-nitropyridine. The method has the advantages of cheap and accessible raw materials and low cost, does not use a diazotization hydrolysis reaction, is safe, simple and convenient to operate, does not use mixed acid, is less in wastewater yield and environmentally-friendly, does not use a nitration reaction, is high in reaction selectivity, few in side reactions, simple in post-treatment and high in product yield and product, and is suitable for industrial production.
Preparation method of high-yield 2-chloro-5-nitropyridine
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Paragraph 0052-0057, (2019/04/02)
The invention relates to a preparation method of high-yield 2-chloro-5-nitropyridine. According to the method, 2-halogenated acrylate serves as an initial raw material and is sequentially condensed with nitromethane and triethyl orthoformate and cyclized with pyridine to obtain 2-hydroxy-5-nitropyridine, and then the 2-chloro-5-nitropyridine is prepared by chlorination. Used raw materials are lowin cost and easy to obtain, operation is simple and convenient, conditions are mild, nitration reaction is omitted, wastewater quantity is small, operation safety is high, product yield and purity arehigh, and the cost is low.
